After putting in 65 hours of research, comparing more than 110 portable air conditioners and testing 11 of the best models, we recommend the Whynter Elite ARC-122DS. However, bear in mind that because portable air conditioners are housed entirely indoors they’re extremely inefficient, and in very hot weather they can struggle to do the job at all. Dual-hose models like the Whynter are more efficient and effective than single-hose models. But, if possible, you should use a window or wall AC instead—they work better, usually cost less, and don’t take up as much space.

Buying Options

The dual-hose Whynter Elite ARC-122DS is our favorite portable AC because we think it has the best cooling performance. In our tests, we found that it draws the least infiltration air—that is, hot air sucked in from outside the room that you’re trying to cool. It’s also one of the quietest models we have found, and is significantly smaller and lighter than its closest competitors. Energy use info for portable ACs is hard to pin down, but we believe this Whynter is one of the most efficient models, if not the most efficient. On the downside, installing the ventilation hoses can be frustrating, but that’s typical of any portable AC. And though Whynter claims this model can cool a 400-square-foot room, we think 250 square feet is more realistic: All portable ACs fall way short of manufacturer claims in our experience.

Buying Options

If our main pick is sold out, consider the Whynter Elite ARC-122DHP. It is the same air conditioner as our main pick, but it also has a built-in heater as well as a drain pump (which can come in handy in oppressively hot and humid areas). It’s slightly heavier and costs more than the AC-only model, though.

Buying Options

The Haier HPND14XCT is another great dual-hose portable AC. It’s even quieter than our top pick. However, it’s also significantly bigger and heavier, and usually won’t cool a room as effectively because it draws in more infiltration air (though still less than most models we tested). It has a larger advertised cooling capacity than our main pick (14,000 Btu) but it’ll still be most effective in spaces around 250 square feet. As of May 2018, this Haier is tough to find in stores, so we may swap out this recommendation if it’s replaced by a new model or otherwise becomes unavailable.

Buying Options

If you plan to use your portable AC only occasionally—like during a brutal heat wave that’s making sleeping difficult—or if the air you’re trying to cool isn’t distressingly hot and muggy, a single-hose model can be OK. We like the Honeywell HL10CES the most. It’s cheaper than our other picks, relatively small and light, easy to roll around and install, and very quiet. To be clear: It’s much less effective and efficient than our dual-hose picks, and will struggle to cool off a room on a very hot day. But it works fine as a spot cooler (blowing cold air directly at your body). And if you plan to use it only a few weeks per year for a few hours at a time, the extra energy use won’t cost you very much, anyway.

Portable air conditioners frequently come in and out of stock during the summer months, and there’s a chance that when you read this guide none of our picks will be easy to find. If that’s the case and you can’t wait for our picks to return to stores, grab whatever dual-hose unit is available and affordable—none of them are terrible.

Why you should trust us

Since 2015 we’ve put in about 65 hours of research and testing on portable ACs, including 16 hours of new testing for this latest version of the guide. All told, we’ve looked at 112 different models, and we’ve tested 11 of the best.

Much of our research consisted of reading through extensive documentation from the US Department of Energy, including the final rule on forthcoming portable air conditioner efficiency requirements, which outlines testing standards for the industry. We also gathered important insights from a Swedish engineering dissertation (PDF) on how these things are designed, marketed, and optimized. We interviewed appliance-efficiency experts, including Joanna Mauer, the technical advocacy manager for the Appliance Standards Awareness Project, and Lauren Urbanek, senior energy policy advocate at the Natural Resources Defense Council. And we spoke with representatives from a few portable AC brands, including De’Longhi, Haier, and LG.

Tyler Wells Lynch has covered air conditioning for more than two years, and has also covered space heaters, fans, stoves, and clothes dryers for Wirecutter. Liam McCabe is Wirecutter’s appliance editor, and has been writing about air conditioners for Wirecutter for five summers, including older versions of this guide.

Who should get this

Portable air conditioners should be thought of as your last resort for getting cool. Compared with window ACs, portable models cost nearly twice as much, use a lot more energy, and take up much more space. More important, they don’t work very well in really hot weather. On a 90-degree day, most will struggle to lower room temperatures to 80 degrees Fahrenheit. In relatively mild climates, a strong fan or evaporative cooler might do the trick for a lot less money.

However, sometimes portable ACs are the only option. In a basement or garage, for example, the windows can be too small to accomodate a window AC. The same can be true if you have casement windows (which swing open on hinges, like a door) or sliding windows (which move along horizontal rails). However, Frigidaire makes an AC designed for these windows—it’s much more efficient than any portable AC and should be your first choice if it will fit.

Contrary to what the name suggests, portable ACs are not very easy to install. The job involves bracket kits, screws, foam insulation, snap-on hoses, and the tools needed to fasten the whole apparatus to your window frame, the ease of which varies from window to window. It can actually be quite frustrating. This is yet another reason we think a window AC is a better choice if you can use it, even if you need it only a few weeks each year. Again, they’re cheaper and they work better—and they’re also smaller, arguably easier to install, and easier to pack away in the off-season.

Why don’t portable ACs work well?

Air conditioning works by moving heat from the inside to the outside of your house. Most types of air conditioners are designed to sit at least partially outdoors, where the heat can just passively radiate away. But a portable AC sits entirely indoors, so it needs to actively push the heat up an exhaust hose that ventilates through a window (sort of like a clothes dryer). It’s quite an uphill battle.

This design has several bad side effects. The worst is that it pulls warm air into the room through cracks around doors, windows, and floorboards. By forcing air out through the exhaust, it creates negative pressure in the room (a slight vacuum), and “infiltration air” seeps in to equalize the pressure. In very hot weather, this is a huge problem. When it’s 95 degrees outside, the infiltration air can erase up to 96 percent of a portable AC’s cooling effect, as the Department of Energy found (PDF) for one particularly bad model. All portable ACs draw some infiltration air, but single-hose models can be particularly sucky, pulling about three times as much as dual-hose models.

Another side effect is that a portable AC’s exhaust system wastes a bunch of cold air. Other types of ACs keep indoor and outdoor air almost totally separate: Indoor air gets cooled as it passes over the evaporator, outdoor air takes the heat off the condenser. But a portable AC uses some indoor air—which it already took the time and energy to cool off—to take heat off the condenser, and then dumps it outside. This is just not an efficient way to do things. Dual-hose models are better because they have a separate intake-exhaust loop that relies mostly on outdoor air to cool the condenser, and they waste only about one-third as much indoor air as single-hose (exhaust-only) models do, the DOE found (PDF).

Finally, the body and hoses radiate some heat back into the room before it all gets pushed out through the exhaust. The DOE determined that, on average, a portable AC’s hoses radiate about 3 Btu per square foot, while the body casing radiates enough heat to offset about 2 percent of cooling. Those are not huge amounts, especially if you keep the hoses short. But combined with all the other inefficiencies, they add up.

A portable AC’s exhaust system wastes a bunch of cold air.

Across the board, the DOE found (PDF) that the real-world cooling capacity of portable ACs was much less than the advertised amount. Even in just moderately hot weather, around 82 ºF, most of the portable ACs that the DOE tested cooled at only about 7,000 Btu—even when they claimed to cool at 13,000 Btu. That means you’ll probably end up using more energy than you expect, too, though the numbers aren’t too bad. Under very basic and generous calculations, the most efficient dual-hose portable AC would add about $21 per year to your energy bill, compared with a run-of-the-mill Energy Star window AC meant to cool the same area. A harsher estimate, factoring in all the inefficiencies even for a dual-hose model, could be more like $60 extra, or about twice as much as the window unit. The truth is probably somewhere in the middle. According to Natural Resources Defense Council senior energy policy advocate Lauren Urbanek, a portable AC that meets the upcoming DOE minimum efficiency rule (which we believe our pick would meet) will cost about $96 to run each year on average, $36 more than running a comparable window unit would cost.

How we picked

Portable ACs all use the same technology, but they vary in size and appearance. Photo: Liam McCabe

This guide has done something of a 180 since we first published it. Back in 2016 we committed ourselves singularly to single-hose models, favoring them as cheaper and more portable. The following year we did the opposite and dismissed all single-hose models for being too inefficient. This year we think we’ve struck the right balance of recognizing the unique value in both types.

We considered both single- and dual-hose models, but gave a preference to the latter. A dual-hose portable air conditioner usually cools a room faster, using less energy overall, than a single-hose design, especially in very hot weather. The DOE has concluded that dual-hose models use about 15 percent less energy than single-hose models on average—not huge, but not nothing either. In very hot weather, dual-hose units have an even greater advantage.

But if you just need something to take the heat off, a single-hose model may be a better choice. Not only are they easier to find, they tend to be cheaper, smaller, easier to install, and easier to move from room to room. If you plan to use it only occasionally, you won’t notice a big difference on your energy bill anyhow. It may not be able to cool off an entire room on a very hot day, but it’ll still feel good when you sit in front of it and let it blast you with cold air.

With such a huge field of contenders, we decided to focus on models with a high energy-efficiency ratio, eliminating most with an EER below 9.0. The EER spec is measured as the Btu rating divided by the maximum wattage, and a higher number is better: It means you get more cooling per watt consumed. An EER around 10 is pretty good, though we’ve seen it as high as 12. Picking an air conditioner (portable or otherwise) that needs less energy for the same cooling power is just a common sense thing to do. But the stakes are a little higher for portable ACs because of all the other inefficiencies. A model that uses less energy also radiates less heat back into the room, doesn’t need as much air to cool the condenser, and potentially draws less infiltration air.

We then homed in on models with the strongest owner ratings, because good ratings usually indicate good reliability. But in general, portable ACs have mediocre reviews, with even the best-liked models barely earning an overall rating of four stars out of five, in the same sad company as inkjet printers. (The best window units earn a solid 4.2 or 4.3 stars out of five.) Most of these low scores are due to people not doing their research and expecting the thing to work as well as a window unit. Nonetheless, some portable ACs are rated much worse than others, often because owners report that their plastic parts become brittle and crack after just one summer. So we cut the lowest-rated models of the bunch.

A dual-hose portable AC usually cools a room faster, using less energy overall, than a single-hose design, especially in very hot weather.

A fair price for a portable AC with these features is somewhere in the range of $325 to $400 for single-hose, and $400 to $500 for dual-hose. Paying much more than that doesn’t get you any worthwhile advantages that we can find, so we cut any that cost more than this.

The advertised decibel ratings for these machines don’t offer a good idea for how loud they’ll actually be—one, because most people don’t know how loud “54 decibels” is, and two, because actual volumes are almost always louder than manufacturer claims. That’s why our noise tests are so important. But in narrowing our picks we did dismiss any with an unusually high advertised rating—anything higher than 56 dB.

Cooling capacity, measured either in Btu or square footage, seems important but had only a slight impact on our picks. Manufacturers rate all these machines to cool 400 square feet or more, but that’s highly optimistic. Both the DOE (PDF) and Consumer Reports (subscription required) have found that portable ACs often struggle to cool as much space as they advertise being able to. In fact, DOE testing showed that the actual cooling capacity can be barely half of what’s listed. So for this guide, we’ve cut the manufacturers’ square-footage ratings roughly in half, and our experience shows this to be a more accurate figure. So just go big with the cooling capacity—better to overestimate than underestimate the cooling power you need.

We’ve found that portable ACs are very likely to come in and out of stock throughout the summer months, and you might have difficulty finding our picks sometimes. But some brands are worse than others at keeping their products available, so we dismissed any models with particularly thin availability. The brands behind those hard-to-find models tend to have indifferent, unresponsive customer service as well.

Some portable ACs have a pump that can push condensation up through a hose to drain, though it’s uncommon. That can come in handy in super-humid climates, if you’re running the machine all day. (Without it, you’ll have to set up a drainage hose so that it drains downward into a bucket or floor drain; in milder climates you don’t need to worry about drainage at all because the condensation just evaporates through the vent hose quicker than it accumulates in the reservoir.) We didn’t consider the pump to be a necessary feature.

Big, smooth-rolling casters play the biggest part in making a portable AC easy to move, though the unit itself being lightweight helps, too.

How we tested

In the four years we’ve covered portable air conditioners, we’ve done tests for temperature, noise, humidity, airflow, efficiency, and portability. But in that time we haven’t gotten any closer to developing a system that can reliably and consistently measure the cooling performance of a given model. This is an unusually difficult category for testing, and even the Department of Energy acknowledges in its 122-page Final Rule that there are simply too many variables influencing how well an AC performs. Daily weather, humidity, climate, exposure to sunlight, exposure to shade, air drafts, and time of year all need to be tightly controlled from test to test in order for the data to be reliable. All of that is made more difficult by our need to test in the spring in order to publish this guide in time for the summer. This year, outside temperatures wavered from 50 °F to 90 °F over the course of our testing period. There’s no sense, then, in claiming with certainty that any particular AC is going to cool a room faster and more completely than another. It’s best to focus on basic functionality (does it cool well enough?) and then turn to experience-based things like noise level, portability, and ease of use.

That said, we did find a way to measure how much infiltration air a machine is likely to draw into a room. Infiltration air loosely correlates with a machine’s overall efficiency and, in all likelihood, its performance, too. According to the DOE, in dual-hose units the infiltration airflow rate is equal to the exhaust flow rate minus the intake flow rate from outside. For single-hose, it’s equal to the condenser exhaust airflow rate. We used a handheld anemometer to get a basic air velocity rate (in feet per minute), then multiplied that figure by the duct area (in square feet), and weighted the results (as described here) to arrive at a general infiltration airflow measurement in cubic feet per minute. We did this for each intake and exhaust vent in each model we tested.

To test noise, on the advice of audiovisual expert and Wirecutter contributor Geoff Morrison we connected a calibrated microphone to an iPhone 7, launched the SPLnFFT Noise Meter app, and set it to a C-weighting with a slow response. Basically, that weighting accounts for high-frequency aberrations that irritate human ears but don’t necessarily register a high volume. For each unit, we measured the volume by averaging six readings—iterations of each unit’s fan/mode settings (compressor on/off, fan high/medium/low)—from a distance of about 6 feet. We measured the frequency output and looked for isolated spikes in the upper midrange and high frequencies, which tend to sound irritating.

We also hooked up each unit to a Kill A Watt electricity-usage meter to gauge the advertised energy use against the real-world figures. We also used this data to calculate our own energy efficiency ratings just to see how they compared with the advertised ones.

Finally, we did livability tests. We hauled the units around an apartment, comparing the maneuverability of the casters and how smoothly they rolled over thresholds and carpeting. Some ACs have handles located along one half of the unit, making for an awkward, uneven lift, so we made sure to dock points from any unit that was difficult to carry up or down stairs. We noted the general construction quality of the plastic housing and controls, and compared size and weight and how easy the units were to install and uninstall. (A good AC will come with plenty of insulation foam and a bracket kit that spans the full range of window sizes.) We tested the remotes, noting how well the machines responded to commands, if they had a thermostat display, and how easy they were to operate. For a couple of days we were lucky enough to test in the middle of a spring heat wave, with outside temperatures grazing 90 °F. This gave us a chance to do some basic “comfort tests” on our favorite models.

Buying Options

If you need a portable air conditioner, we recommend the Whynter Elite ARC-122DS, a dual-hose unit. It’s quiet for a dual-hose machine, and drew the least amount of infiltration air of any model we tested. The price and installation kit are typical for the category, but it’s much lighter and smaller than similar ACs, so it’s easier to move and store. It’ll work in spaces of up to 250 square feet.

The Elite ARC-122DS has the best specs of any portable AC we’ve come across. It’s a dual-hose model, with a category-leading energy efficiency ratio of 12.0, and a strong 12,000 Btu cooling capacity. As we’ve learned, the printed specs don’t always translate to the real world, but considering the specs plus a bit of our own testing, we can say that the ARC-122DS is likely the most effective cooler among portable ACs. We calculated an infiltration airflow rate of 89 cfm—far and away the lowest of any machine we tested in 2018, and a good indication of both efficiency and performance. Because the EER is so high, this model doesn’t radiate as much heat from its body back into the room. So it should cool rooms quickly and reach lower temperatures than less-efficient models—both of which can have a big impact on your comfort in very hot, humid weather.

As hard as it is for us to objectively measure performance, we did get a chance to try out the ARC-122DS on a 90 °F day—it made the room feel comfortable, for whatever that’s worth.

We tried to measure its energy use as well. Take these findings with a grain of salt, because all sorts of things can affect the power draw. But here’s what we found: In mild weather, the ARC-122DS used about 1,005 watts to run the compressor with the fan on the highest setting, just about matching the advertised power draw (1,000 watts). In tests on a hotter day, it drew 1,080 watts. In another test, we measured 1,100 watts. Calculating against the Btu rating, that suggests the ARC-122DS has a higher efficiency than most portable ACs.

In our 2018 tests the ARC-122DS produced some of the quietest decibel figures of any AC. The compressor, which initiates the cooling cycle, is by far the loudest part of any air conditioner. With the compressor on and the fan at the highest setting, the ARC-122DS averaged 59.9 dBC. Most of the units we tested measured around 63 dBC at this setting. (Only our top-pick single-hose unit was comparably quiet.) With the compressor off and the fan running the ARC-122DS was quieter, but not by as much as you might expect. The fan was actually louder than the two other dual-hose models we tested in 2018, suggesting it’s the compressor, not the fan, that’s unusually quiet.

The ARC-122DS is noticeably more compact than its closest competitors, and much lighter, too. It weighs about 57 pounds, stands a shade under 30 inches tall, and measures 17 inches wide. That’s much smaller and lighter than most dual-hose machines. In fact, it’s about 6 pounds lighter and 2 inches shorter than our single-hose pick (even though single-hose ACs tend to be more compact). As a result, we found it comparatively easier to roll around, even across rugs and over thresholds (not to mention carrying it into a house from the driveway). It doesn’t dominate a room visually the way bigger machines can, and it’ll also take up less space in a small closet or storage area when it’s not in use.

In other aspects, the ARC-122DS is typical of dual-hose models. It comes with the same installation kit as our other finalists. The control scheme and remote control are also pretty much the same—no real complaints to note. Testing the same unit for the second year in a row, we didn’t find any reliability problems; it worked just as well and showed no signs of wear and tear, even after carrying it up a flight of stairs, throwing it in the back of a car, and moving it to a different home on the other side of Boston.

The price (at the time of this writing, at least) is right in line with that of our other finalists, and reasonable for a dual-hose portable AC. User reviews on Amazon and Home Depot are somewhat above average for a portable AC, with most complaints reflecting the efficiency flaws inherent to all portable ACs, or the lack of foam insulation, which we cover below.

Our runner-up pick, the Whynter Elite ARC-122DHP, is the same exact machine, with an added heating element and drain pump.

Flaws but not dealbreakers

For starters, the Elite ARC-122DS is still a portable air conditioner, with all the problems inherent to that design. That means it may not work as well as you’d hope on a sweltering-hot day in August.

The accompanying window kit is not supereasy to install. It consists of a few plastic pieces that slide together, so you can mix and match to the width (or height) of your window—except that it won’t always fit. The double-hung windows used in last year’s test, for example, were about 3 inches too wide for the smaller piece to fill the gap, and at least 6 inches too narrow for the longer piece to fit. (We cut one of the pieces down to size by drilling holes in a line through the plastic until we could bend it enough to snap off, but a saw might be easier, and filling the gap with foam board could work too.) Surprisingly, this was an issue we noticed with at least three other bracket kits. Why is it so hard to build a bracket kit that can span any window width? Doesn’t the portable design of these things suggest you won’t need to a saw to install them? Frustrating.

It also doesn’t come with any foam tape or foam strips to insulate the gaps in the window kit, which is essential to maximize the efficiency and performance of the AC. All that said, this is the same window kit that comes with a lot of competitors. Extra foam is cheap and easy to find, and worth getting.

Buying Options

The Whynter Elite ARC-122DHP is the same air conditioner as our main pick, with the addition of a heater and a drain pump. That means it can double as a space heater during cold weather, and automatically pump water out of the condensation tray, instead of needing manual emptying. Those are some nice perks, but most people won’t have much use for either of them. Condensation, especially, is only an issue in extremely hot and humid conditions; most of the time, any condensation evaporates and gets vented through the exhaust hose. So unless you know you need these features, pick whichever model costs less at the time of buying or is more easily available.

Buying Options

If our main picks are unavailable, or their prices jump, the Haier HPND14XCT is a good alternative. It’s got a higher cooling capacity (14,000 Btu) than our top picks, and in our testing it drew in the second-least infiltration air, meaning it can be expected to work quickly and efficiently. It’s also the single quietest dual-hose AC we tested in 2018. You should expect most of the usual headaches associated with big, bulky portable ACs: It’s really heavy, and the window kit is a hassle to install (though it comes with plenty of foam insulation). It’s also quite a bit bigger and, hence, less portable than our top pick. But its design is still quite compact for a dual-hose unit, and includes a useful holder for the remote.

One word of caution: At the time of writing (May 2018), the Haier appeared to be in short supply at major retailers. Air conditioner inventory is highly seasonal, so it’s possible this year’s deliveries haven’t arrived yet.

We calculated Haier to have the second-lowest infiltration airflow of any machine tested this year at 187 cfm—but that’s still double our main pick’s. Still, compared with most other models, it should be relatively quick and efficient at cooling a room.

The Haier HPND14XCT is also one of the quietest ACs we tested this year, beat only by our top-pick single-hose model. With the compressor on and the fan at full blast, we recorded a decibel reading of just 60.5 dBC, an insignificant half-decibel higher than our top pick. With the compressor off, the fan varied between 52.7 and 55.7 dBC, depending on speed. That averaged out to 57.05 dBC—the quietest dual-hose tested and the second-quietest portable AC overall.

Though short at a mere 29 inches tall (our top pick is 30 inches), the HPND14XCT is pretty heavy. Its 84 pounds (27 more than our top pick) are very noticeable when you try to lift the thing, a task made more challenging by the location of the handles. They’re mounted on the back half of the machine, making for an annoying, front-heavy lift. The caster wheels, however, are smooth enough that we don’t think you’ll find this model that much more difficult to move around than most other dual-hose models.

The HPND14XCT includes insulation foam and covers for the vents, but we weren’t big fans of the window kit itself. The hoses were oddly heavy, and the installation process involved a bit too much screwing and snapping than anyone should have to deal with. It’s not a dealbreaker, because frustrating installation comes with the territory of portable ACs, but it’s still worth noting. We appreciated the holder for the remote at the front of the machine, a design feature that was lacking in every other machine we tested this year. And we had no complaints about the remote and control panel, both of which were responsive and easy to figure out.

We found the advertised EER to be surprisingly low—a mere 8.5, the bare minimum for our consideration. This could be due to the higher cooling capacity, or it could just draw a ton of power. Our own wattage calculations were quite low, which made the calculated EER much better at 11.86, but it really depends on a lot of circumstances, such as weather, humidity, and draft. More important, we’re confident in the HPND14XCT model’s low-infiltration airflow; we think those two findings add up to a better indication of cooling performance than the advertised EER.

Buying Options

If you’re not super-concerned with performance during a heat wave, and just need something to take the edge off at night or in a small, overly warm apartment, the Honeywell HL10CES is a good option. It has one of the highest efficiency ratings we’ve seen, and it produced the single quietest operation of any AC we tested this year. It didn’t come with any foam insulation, which is annoying, but it’s almost $100 cheaper than our top pick and has relatively strong user reviews for a portable AC. Given the inherent inefficiency of the single-hose design, we would suggest the Honeywell for only spaces below 200 square feet.

With an EER of 11.4 and a cooling capacity of 10,000 Btu, the Honeywell HL10CES is the second most efficient AC we tested this year, at least on paper. Our own calculated EER put it in similar territory. In our tests we calculated an infiltration rate of 210.42 cfm of outside air, which is significantly lower than that of most ACs we tested this year. (For comparison, our previous runner-up dual-hose pick drew an infiltration airflow rate of 358.2 cfm.) However, the Honeywell also advertises an airflow capacity of 241 cfm. That suggests a net of just 30 cfm of cooled air—a stark reminder of the inherent inefficiency of the single-hose design.

The HL10CES proved the single quietest portable AC we tested this year. With the compressor on and the fan at full blast, we recorded a decibel rating of 59.9 dBC. Only our top-pick dual-hose matched that. With the compressor off the decibel range fell to a mere 50.4 to 53.2 dBC, making for an average rating of 55.6 dBC—far and away the quietest. You might think this was due to a weak fan, but the fan’s advertised cfm (241) is the highest of any air conditioner we tested this year. It’s just a quiet machine.

But it’s not a very small machine, at least not compared with other single-hose models, and its weight is slightly above average at 66 pounds (our top pick is 57 pounds). We found the casters smooth enough, though, and the evenly spaced handles made it easy to lift the machine over thresholds and other obstacles. We also appreciated the holder for the power cord—something we didn’t find in any other AC.

The HL10CES has a modern, almost medical look to it, and the tilted control panel makes operation a bit easier than other top-oriented control systems. The remote was highly responsive, with a digital display for temperature and setting. This model also has relatively solid user reviews on Amazon and Best Buy, with most of the complaints having to do with shipping problems or the usual performance qualms you’ll find with any portable AC.

The competition

The dual-hose Avallon APAC140C did fine in our tests. But it uses more energy (both on paper, with an EER of 9.5, and in practice, drawing 1,450 watts in our test) than our main pick and runner-up, it doesn’t obviously cool better than either Whynter model, and it’s as large as our bulky runner-up. It doesn’t really have a control panel, either, just a remote control, so if you lose that, working the machine is going to be tricky. It’s very similar to the Whynter models on many counts. Its price is about the same as that of our other finalists, too. We just don’t think there’s a real compelling reason to buy this model. A lower-powered version, the APAC120S, is also available but much harder to find.

Whynter makes about a half-dozen other dual-hose models. The Whynter ARC-14S was our also-great pick in 2016. In the 2017 tests it showed a really high volume of infiltration air for a dual-hose AC (287.91 cfm), and proved somewhat louder than the Haier. We were also turned off by how big and heavy it is. The ARC-110WD and ARC-131GD got the boot because of dozens of owner ratings that cited poor reliability. Others in the lineup, including the ARC-12SD, ARC-126MD, and many more, all had minor issues such as limited availability, a higher price, or lower efficiency. Among Whynter’s single-hose units, we tested the Whynter ARC-12S and dismissed it for being too loud and drawing too much infiltration air. It’s also pretty ugly and less efficient than our top-pick single-hose.

We considered but dismissed about a dozen other dual-hose models from CCH Products, EdgeStar, Friedrich, Haier, Impecca, and Sunpentown because they’re hard to find, overpriced, inefficient, poorly rated, or a combination.

Among single-hose units, we also tested the Honeywell MN10CESWW, Black+Decker BPACT12WT, and LG LP1217GSR. The Black+Decker and the LG are among the top-selling portable air conditioners at Home Depot, so we were especially interested in them. But the Black+Decker proved to be one of the loudest we have measured, topping out at more than 66 decibels—versus 59 for our top pick. The LG is not particularly quiet, either, at 63 decibels on high. We took a look at but didn’t test another, very similar LG top-seller, the LP1215GXR. The top-selling LG LP1015WNR (3.6 stars across almost 900 reviews at Home Depot) is an older design, around since at least 2014. It has more than 125 one-star reviews, with frequent complaints that the machine is too loud for sleep and is difficult to drain when condensation builds up.

In all, we looked at 28 different single-hose models, from these manufacturers and others, including Emerson, Haier, Frigidaire, and Sunpentown. Shaky reviews, concerns over specs like noise and efficiency, and price and availability issues led us to dismiss them.

What to look forward to

As with just about every other appliance category, we expect more “smart” portable ACs to trickle out over the next few years. The Frigidaire Gallery FGPC1244T1 is the only one that’s currently available. You can control most of its functions with a smartphone app, or with Alexa or Google Home. However, it’s really expensive for a single-hose unit, and we don’t think those added connectivity features are worth the added expense. All the smart window ACs we’ve seen so far have proven to be pretty glitchy, and we’d expect the same problems to pop up with this portable model, too.

You may have an easier time finding an effective, efficient portable AC in a few years. In 2016, after a years-long process, the Department of Energy approved a rule that would require all portable ACs to use at least 20 percent less energy than the least-efficient models that are currently available. It was scheduled to be added to the Federal Register in March 2017, but the current administration delayed that step. Earlier this year a district judge ordered the standards implemented, but then in April 2018 another court allowed the delay to continue. As of this writing the standards remain in limbo. If this rule is finally solidified, the new efficiency standards will take effect in 2021.

Even then, portable air conditioners will still use much more energy and provide a worse cooling experience than window air conditioners. Several groups advocated for even-stronger standards. But as Lauren Urbanek, senior energy policy advocate for the Natural Resources Defense Council, put it: “We’re happy that there’s a standard to begin with. These products were very far behind window AC efficiency and using way more energy than they needed to.”

Care and maintenance

We know a few tricks to improve the efficiency and performance of any portable AC:

Keep the AC as close to the window as you can, with as many of the accordion ribs collapsed as possible.

Stuff the gaps around the window fixture with foam insulation strips. Some units come with foam tape, but not our main pick or runner-up, unfortunately. If you need some, 10 feet of the stuff typically costs about $5. The tape will help prevent warm air from slipping in through cracks as easily.

When using the AC, keep it as close to the window as you can, with as many of the accordion ribs collapsed as possible, so the hose or hoses stay short. A short hose radiates less heat back into a room than a long hose. The radiation offsets maybe 1 percent of the AC’s cooling, so it’s a minor problem, but an easy one to fix. If you’re very worried about this effect, you can insulate the hose or hoses with duct wrap.

Clean the filter at least once a month. You don’t need any tools for this—it’s just like cleaning the lint filter in a clothes dryer. A dirty filter makes an AC less efficient and effective, and it takes only about one minute to fix.

Wirecutter is a list of wonderful things by Brian Lam and friends, founded in 2011 and a part of The New York Times Company since 2016. Have a question? Just ask.